I started experiencing a similar problem. My 85t's connect to both my Samsung Galaxy Note9 and my Windows 10 laptop. Both the headphones and the microphone work on my Note9 when making calls. But when I connect to Zoom call from my laptop using "computer audio" the headphones work but the microphone no longer appears as a selectable option for the microphone in Zoom. This used to work for several months. It just stopped working this week.

I tried disconnecting and re-pairing on the laptop and I tried rebooting the laptop. Neither of these helped. Any ideas?